Comments on Truck Splash and Spray Reduction for a Report to Congress

DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

[Docket No. NHTSA-99-5101; Notice 1]

Comments on Truck Splash and Spray Reduction for a Report to

Congress

AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT.

ACTION: Notice requesting comments.

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SUMMARY: The Senate Appropriations Committee has directed NHTSA to

provide Congress with a report updating the agency's research on truck

splash and spray by conducting a comprehensive review and evaluation of

spray suppression measures that can be employed on heavy duty vehicles

to provide clearer highway visibility and safety during periods of

adverse weather conditions. The report is due to Congress by October

21, 1999. This notice invites any interested person to provide NHTSA

with any information or data in this area that the person believes

NHTSA should consider in preparing this report to Congress.

DATES: All comments received by NHTSA no later than June 21, 1999 will

be considered in preparing this report to Congress on progress in heavy

vehicle splash and spray suppression.

ADDRESSES: All comments should refer to Docket No. NHTSA-99-5101;

Notice 7 and be submitted to: Docket Management, Room PL-401, 400

Seventh Street, SW, Washington, D.C. 20590. Docket hours are from 10:00

a.m. to 5:00 p.m. Monday through Friday.

For public comments and other information related to previous

notices on this subject, please refer to Docket No. 83-005, NHTSA

Docket, Room 5111, 400 Seventh Street, SW, Washington, DC 20590. NHTSA

Docket hours are from 9:30 am to 4:00 pm Monday through Friday.

FOR FURTHER INFORMATION CONTACT: Mr. Jere Medlin, Office of Crash

Avoidance Standards, NPS-20, National Highway Traffic Safety

Administration, 400 Seventh Street, SW, Washington, DC 20590, telephone

(202) 366-5276, fax (202) 366-4329.

SUPPLEMENTARY INFORMATION: The terms ``splash and spray'' are commonly

used to describe the adverse effects on driver visibility caused by

other vehicles when traveling on wet roads. While spray clouds are

produced by all vehicles traveling on wet roads, those produced by

large trucks and buses are much larger than the clouds produced by

passenger cars and light trucks. This can result in reduced driver

visibility for adjacent motorists and for the driver of the large truck

or bus.

NHTSA and others have studied the subject of splash and spray for

more than 30 years. The most recent time the agency evaluated this

subject was in late 1993, in response to a request from the Senate

Appropriations Committee. In its report on NHTSA's FY94 appropriation,

the Committee asked that the agency report ``* * * on the status of

recent technological progress in the design and testing of splash and

spray suppression devices [for large commercial vehicles] and NHTSA's

view on the need for regulation in this safety area.'' In response,

NHTSA submitted a report to Congress in March 1994, ``Splash and Spray

Suppression, Technological Developments in the Design and Testing of

Spray Reduction Devices for Heavy Trucks'' (DOT HS 808 085), copies of

which are available from the National Technical Information Service,

Springfield, Virginia 22161. The report provided a comprehensive

evaluation and summary of available data and studies conducted before

and after NHTSA terminated rulemaking on splash and spray in 1988. The

1994 report concluded the following about developments in splash and

spray reduction for heavy trucks:

1. There are no data available to support the position that

heavy truck splash and spray presents a major safety problem, in

terms of crashes caused and injuries in those crashes. The greatest

involvement ever found for splash and spray was that it was a factor

in 0.41% of crashes studied according to a 1959 British study. A

more recent study in Indiana found that splash and spray could not

be documented as a cause of any crash studied, and a North Carolina

study found that splash and spray was a factor in 0.0055% of 450,000

crashes evaluated. No information has become available since 1988

suggesting that splash and spray is a larger safety problem than was

previously known.

2. No study or other information has become available since 1988

that would cause the Agency to change its previous determination

that no technology or combination of technologies has been

demonstrated that will consistently and significantly reduce splash

and spray from tractors, semi-trailers, and trailers to the extent

that driver visibility will be significantly improved.

3. Several manufacturers of large trucks believe that

aerodynamic improvements, which were made to their vehicles in an

effort to improve fuel economy and reduce operating costs, will also

serve to reduce splash and spray. This belief is based on very

limited testing under controlled conditions. More extensive testing

conducted in connection with NHTSA's previous rulemaking indicated

that aerodynamic devices are not as effective at suppressing spray

in the presence of crosswinds. Previous engineering analysis

suggested that aerodynamic devices on truck tractors would not be

effective at reducing spray when the tractor was connected to a

trailer or semitrailer that was not a van. The testing done to date

by truck manufacturers of more aerodynamic tractors has not examined

these previously identified concerns to see if they are still valid.

4. The truck manufacturers appear to be working to reduce the

splash and spray generated by their vehicles in the absence of any

government requirement for them to do so. In addition to the efforts

of Freightliner and Paccar in testing more aerodynamic truck

tractors, the SAE has worked for years to develop a consensus test

procedure that can be used to evaluate the performance of spray

suppression devices.

Given these circumstances and the information available to it,

the Agency has no plans to initiate a new rulemaking action on heavy

truck splash and spray reduction.

More recently, in its report on NHTSA's appropriation for fiscal

year 1999, the Senate Committee on Appropriations has again asked the

agency to review this matter as follows:

Spray suppression research.--The Committee acknowledges the work

previously undertaken by NHTSA in the area of spray suppression

research and evaluation of abatement technologies and continues to

support further research by NHTSA in this area to make travel on the

Nation's highways safer and less stressful. The Committee is aware

of the progress made in the European Union in designing beneficial

performance standards and implementing roadway spray suppression

regulations to improve highway visibility. The Committee directs

NHTSA to update its research by conducting a comprehensive review

and evaluation of spray suppression measures that can be employed on

heavy duty vehicles (over 8,500 pounds gross vehicle weight rating)

to provide clearer highway visibility and safety during periods of

adverse weather conditions. NHTSA shall publish and report its

findings to Congress within 12 months of enactment.

The agency has begun gathering the information it will need to

respond to this request. NHTSA will conduct a comprehensive review and

evaluation of spray suppression measures that can be employed on heavy

duty vehicles to update its research since 1993. However, to ensure

that the agency is aware of and considers all relevant information on

this subject when preparing the Report to Congress, NHTSA is publishing

this notice to invite public comment. All interested persons are

invited to provide data and other relevant information which has become

available since 1993, particularly developments that were not included

in NHTSA's 1994 Report to Congress, concerning spray suppression

measures that can be employed on heavy duty vehicles.

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The agency will consider all public comments it has received by

June 21, 1999, when preparing the report to Congress. While NHTSA is

interested in any splash and spray information the public may have to

offer, the agency is especially interested in responses to the

following questions.

Questions

1. Please provide information and data on any technological

improvements made since 1993 in the design and/or testing of splash and

spray devices for use on heavy duty vehicles. NHTSA is especially

interested in supporting data that are the basis for the commenter's

conclusion that the device represents a technological improvement that

will consistently and significantly reduce splash and spray to the

extent that driver visibility will be significantly improved.

2. Please provide information on any data bases that NHTSA should

examine or consider to estimate the extent to which splash and spray

from heavy duty vehicles contributes to crashes on the public roads.

3. In the agency's rulemaking on this subject that was terminated

in 1988, NHTSA indicated that aerodynamic improvements, made by large

truck manufacturers to their vehicles to improve fuel economy and

reduce operating costs, had shown promise for reducing splash and spray

in some situations. That is, if such aerodynamic devices were attached

to a truck tractor pulling a van-type semitrailer and if there were

little or no crosswind present, the devices could improve visibility to

a level that would be helpful to other motorists. In its March 1994

report to Congress, the agency indicated that several large truck

manufacturers believed that aerodynamic improvements made since 1988

would reduce splash and spray. However, this was based on very limited

testing under controlled conditions. The testing done by truck

manufacturers did not examine whether the previously identified

concerns were still valid.

Please provide information on any aerodynamic improvements to truck

tractors since 1993, and data showing to what extent, if any, such

improvements have lessened the amount of splash and spray generated by

tractor/van-semitrailer combinations with crosswinds present. NHTSA had

found in its testing that a crosswind of 8 miles per hour or more

significantly diminished the benefits of the splash and spray

countermeasures that were tested. In a 1987 rulemaking notice on this

subject, NHTSA cited National Weather Service data indicating the mean

wind velocity for the vast majority of the United States is 8 mph or

greater. Similarly, please provide information and supporting data on

other solutions that have been developed since 1993, which lessen the

amount of splash and spray generated by other tractor/trailer

combinations, such as tanks or flatbeds, or other types of heavy duty

vehicles with crosswinds present.

4. Please provide information on any aftermarket devices introduced

since 1993 that are intended to reduce the amount of splash and spray

generated by heavy duty vehicles. Include a specific description of the

devices, a brief explanation of how they reduce splash and spray, and

all tests and other data that demonstrate the devices are effective in

reducing splash and spray across a range of heavy vehicles under

representative weather conditions.

5. If a person believes that some means would be effective at

reducing splash and spray from tractor-single trailer combinations,

please provide any information and data on whether that means would

also work to reduce spray from tractors combined with double or triple

trailers.

6. In its March 1994 report to Congress, NHTSA provided a

comprehensive summary of the data and studies that were conducted

before and after the agency terminated its rulemaking on splash and

spray in 1988. This included all relevant information of which the

agency was aware. NHTSA would like commenters to provide information on

any study or testing of splash and spray suppression measures that was

not considered in the 1994 report to Congress but should be considered

in preparing this report to Congress.

7. Please provide information on the costs associated with splash

and spray devices introduced since 1993, both original equipment and

aftermarket, along with data on how effective the devices are at

reducing splash and spray across a range of heavy duty vehicles and

representative weather conditions.

8. In its current request that NHTSA again review this matter, the

Senate Appropriations Committee stated that ``The Committee is aware of

the progress made in the European Union in designing beneficial

performance standards and implementing roadway spray suppression

regulations to improve highway visibility.'' NHTSA is aware of European

Economic Community (EEC) Directive 91-226, ``Spray Suppression

Systems,'' issued in April 1991. The Directive applies to heavy duty

vehicles and involves EEC member component type-approval addressing two

types of spray suppression devices: (1) energy absorption and (2) air/

water separator. The Directive includes laboratory performance tests of

the devices along with vehicle location and component marking

requirements.

Please provide any information along with supporting data on how

effective EEC Directive 91-226 has been at reducing splash and spray

across a range of heavy duty vehicles and representative weather

conditions, to what extent driver visibility is improved, and whether

U.S. trucks would need additional equipment, like fenders, to achieve

the same visibility benefits from the spray suppression equipment.

9. In 1994 the Society of Automotive Engineers published a

``Recommended Practice For Splash and Spray Evaluation,'' J2245. It

provides general guidelines for measuring splash and spray from

vehicles operating over wet pavements. The guidelines describe two

methods of analysis: (1) video-digitizing and (2) laser. The video-

digitizing method uses video images and contrast measurements between

black and white checkerboards when a spray cloud is superimposed on

them as a means of measuring the obscuring spray. The laser method uses

laser transmittance through the spray cloud as the means of

measurement. The test procedures involve actual test vehicles fitted

with splash and spray devices, and include measurements under various

wind conditions.

NHTSA is interested in any information along with supporting data

on the use of these two test procedures by manufacturers and others.

Specifically, the agency would like to know whether one method is

preferred over the other, and why, along with information on the extent

to which each method represents real world conditions. In addition,

please provide any information on how well reductions in splash and

spray through either method correlate to improvements in actual driver

visibility.

The agency invites written comments from all interested persons. It

is requested that two copies of each written comment be submitted. As

always, NHTSA will try to consider comments that it receives after the

comment closing date. However, in this case, the deadline imposed by

the Senate Appropriations Committee means that comments submitted after

the closing date of June 21, 1999 are less likely to be considered.

All comments must not exceed 15 pages in length (49 CFR 553.21).

Necessary attachments may be appended to these submissions without

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regard to the 15 page limit. This limitation is intended to encourage

commenters to detail their primary arguments in concise fashion.

If a commenter wishes to submit specified information under a claim

of confidentiality, three copies of the complete submission, including

purportedly confidential business information, should be submitted to

the Chief Counsel, NHTSA, at the street address given above, and two

copies from which the purportedly confidential information has been

deleted should be submitted to the Docket Section. A request for

confidentiality should be accompanied by a cover letter setting forth

the information specified in the agency's confidential business

information regulation, 49 CFR Part 512.

Comments on this notice will be available for inspection in the

docket. NHTSA will continue to file relevant information as it becomes

available in the docket after the closing date. Those persons desiring

to be notified upon receipt of their written comments in the Docket

Section should enclose, in the envelope with their comments, a self-

addressed stamped postcard. Upon receipt, the docket supervisor will

return the postcard by mail.

Issued on: May 4, 1999.

L. Robert Shelton,

Associate Administrator for Safety Performance Standards.

[FR Doc. 99-11545 Filed 5-6-99; 8:45 am]

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